Question: What is the main socket type of the sovereign state of Yantai?
Paraphrase: What is the most attachment sort of the majestic state of Yantai?
SPARQL (Wikidata): SELECT ?answer WHERE { wd:Q210493 wdt:P17 ?X . ?X wdt:P2853 ?answer}
Answer: Europlug, AS/NZS 3112, NEMA 1-15